Proposed work for the period 6/01/74 - 5/21/75 will continue to clarify the mechanism of increased cardiac output, systemic blood pressure, pulmonary artery pressure, and left atrial pressure tht occurs with elevated cerebrospinal fluid pressure. Work will continue in an effort to identify a circulating beta adrenergic factor (possibly from the brain) by using an isolated perfused gracillus muscle preparation with alpha adrenergic and ganglionic blockade. Changes in left ventricular compliance will be determined with a sonomicrometer.